ObjectInputStream类readLong()方法 (ObjectInputStream Class readLong() method)

• readLong() method is available in java.io package.

  readLong()方法在java.io包中可用。

• readLong() method is used to read 8 bytes (i.e. 64 bit) of long value from this ObjectInputStream stream.

  readLong()方法用于从此ObjectInputStream流中读取8个字节(即64位)的长值。

• readLong() method is a non-static method, it is accessible with the class object only and if we try to access the method with the class name then we will get an error.

  readLong()方法是一种非静态方法，只能通过类对象访问，如果尝试使用类名称访问该方法，则会收到错误消息。

• readLong() method may throw an exception at the time of reading long.

  readLong()方法在读取较长时间时可能会引发异常。

  • IOException: This exception may throw when getting any input/output error while performing.IOException ：在执行过程中遇到任何输入/输出错误时，可能引发此异常。
  • EOFException: This exception may throw when this stream has reached its end of the file.EOFException ：当此流到达文件末尾时，可能引发此异常。

Syntax:

句法：

    public long readLong();

Parameter(s):

参数：

• It does not accept any parameter.

  它不接受任何参数。

Return value:

返回值：

The return type of the method is long, it returns the 8 bytes long value read.

该方法的返回类型为long ，它返回读取的8个字节的long值。

Example:

例：

// Java program to demonstrate the example 
// of long readLong() method of ObjectInputStream
import java.io.*;
public class ReadLongOfOIS {
public static void main(String[] args) throws Exception {
// Instantiates ObjectOutputStream , ObjectInputStream 
// FileInputStream and FileOutputStream
FileOutputStream file_out_stm = new FileOutputStream("D:\\includehelp.txt");
ObjectOutputStream obj_out_stm = new ObjectOutputStream(file_out_stm);
FileInputStream file_in_stm = new FileInputStream("D:\\includehelp.txt");
ObjectInputStream obj_in_stm = new ObjectInputStream(file_in_stm);
// By using writeLong() method is to write
// long to the obj_out_stm stream
obj_out_stm.writeLong(5411489332534l);
obj_out_stm.writeLong(234773224114l);
obj_out_stm.flush();
while (obj_in_stm.available() > 0) {
// By using readLong() method is to read
//  long from the obj_in_stm
long val = (int) obj_in_stm.readLong();
System.out.println("obj_in_stm.readLong(): " + val);
}
// By using close() method is to 
// close all the streams 
file_in_stm.close();
file_out_stm.close();
obj_in_stm.close();
obj_out_stm.close();
}
}

Output

输出量

obj_in_stm.readLong(): -169460426
obj_in_stm.readLong(): -1449977166

翻译自: https://www.includehelp.com/java/objectinputstream-readlong-method-with-example.aspx